ERL2019 - List of Keywords (cathode)

Paper	Title	Other Keywords	Page
MOCOXBS04	The Berlin Energy Recovery Linac Project BERLinPro - Status, Plans and Future Opportunities	cavity, linac, gun, operation	8
	M. Abo-Bakr, N. Al-Saokal, W. Anders, Y. Bergmann, K. Bürkmann-Gehrlein, A. Bundels, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, S. Heling, J.G. Hwang, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, J. Kühn, B.C. Kuske, J. Kuszynski, A.N. Matveenko, M. McAteer, A. Meseck, S. Mistry, R. Müller, A. Neumann, N. Ohm, K. Ott, F. Pflocksch, L. Pichl, J. Rahn, O. Schüler, M. Schuster, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany H. Huck DESY Zeuthen, Zeuthen, Germany
	Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a SRF based demonstration facility for the science and technology of ERLs for future high power, high brilliance electron beam applications. BERLinPro was designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. Given the recent prioritization of the BESSY II upgrade to the BESSY VSR variable pulse length storage ring, HZB is forced to reduce the project goals of BERLinPro. As a result, the project had to be rescoped with the goal to maximize its scientific impact within the present boundary conditions. We report on the last year’s progress of the building, the warm and cold infrastructure and on the time line, goals nd opportunities for the remaining project run time.
	Slides MOCOXBS04 [13.980 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-MOCOXBS04
About •	paper received ※ 16 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020
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WECOXBS02	High Current Performance of Alkali Antimonide Photocathode in LEReC DC Gun	operation, gun, electron, synchrotron	61
	M. Gaowei, J. Cen, A.V. Fedotov, D. Kayran, D. Lehn, C.J. Liaw, T. Rao, J.E. Tuozzolo, J. Walsh, E. Wang BNL, Upton, New York, USA
	The bi-alkali antimonide photocathode are chosen as the electron source material for the Low Energy RHIC electron Cooling (LEReC) project at RHIC, BNL based on its requirement for high bunch charge and long-time beam operation. This report presents the design and operation of the cathode deposition and transportation systems for the LEReC photocathodes, the cathode performance under the high current operation in the LEReC DC gun, as well as the characterization of the damaged cathodes from the long-time operation.
	Slides WECOXBS02 [2.804 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WECOXBS02
About •	paper received ※ 17 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020
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WECOXBS03	Bench Test Results of CW 100 mA Electron RF Gun for Novosibirsk ERL based FEL	cavity, gun, radiation, electron	65
	V. Volkov, V.S. Arbuzov, E. Kenzhebulatov, E.I. Kolobanov, A.A. Kondakov, E.V. Kozyrev, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, A.A. Murasev, V.K. Ovchar, V.M. Petrov, A.M. Pilan, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, S.S. Serednyakov, O.A. Shevchenko, S.V. Tararyshkin, A.G. Tribendis, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia E.V. Kozyrev, S.S. Serednyakov, N.A. Vinokurov NSU, Novosibirsk, Russia A.G. Tribendis NSTU, Novosibirsk, Russia N.A. Vinokurov KAERI, Daejon, Republic of Korea N.A. Vinokurov UST, Daejeon City, Republic of Korea N.A. Vinokurov University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
	Continuous wave (CW) 100 mA electron rf gun for injecting the high-quality 300-400 keV electron beam in Novosibirsk Energy Recovery Linac (ERL) and driving Free Electron Laser (FEL) was developed, built, and commissioned at BINP SB RAS. The RF gun consists of normal conducting 90 MHz rf cavity with a gridded thermionic cathode unit. Bench tests of rf gun is confirmed good results in strict accordance with our numerical calculations and showed reliable work, unpretentious for vacuum conditions and stable in long-term operation. The design features of different components of the rf gun are presented. Preparation and commissioning experience is discussed. The latest beam results are reported.
	Slides WECOXBS03 [3.201 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WECOXBS03
About •	paper received ※ 14 September 2019 paper accepted ※ 11 November 2019 issue date ※ 24 June 2020
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WEPNEC13	Preliminary Investigations and Pre-Research Scheme of High Average Current Electron Injectors at IMP	electron, gun, high-voltage, SRF	90
	Q.T. Zhao, J.C. Yang, Z.M. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	High average current electron injectors are desired by high average beam power SRF linacs. With respect to the different linac application, different beam qualities are required. Two kinds of electron gun are planned for future projects at IMP, one is thermionic electron gun dedicated for high average current, and another one is photocathode gun which is for high average current and high beam quality or even with high polarization. Current status and development of the high average current electron source are investigated and summarized. The thermionic gun studies are planned and the feasible types of gun for the future Electron ion collider of China (EicC) project are also proposed. The pre-research scheme of these two kinds of electron guns are schemed, which will be the start of high average current and high-quality electron source development at Institute of modern physics (IMP), Chinese academy of sciences (CAS).
	Poster WEPNEC13 [0.827 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC13
About •	paper received ※ 22 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
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WEPNEC17	Developments in Photocathode R&D at STFC Daresbury Laboratory: New Transverse Energy Spread Measurements and the Development of a Multi-Alkali Photocathode Preparation Facility	vacuum, electron, emittance, laser	103
	L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom L.B. Jones, D.P. Juarez-Lopez, B.L. Militsyn, T.C.Q. Noakes, L.A.J. Soomary, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom D.P. Juarez-Lopez, L.A.J. Soomary, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Photocathode R&D activity within ASTeC is focussed on further development of the tools required for the preparation and characterisation of high performance photocathodes for X-FELs. Our Transverse Energy Spread Spectrometer (TESS)* experimental facility can be used with III-V semiconductor, multi-alkali and metal photocathodes to measure transverse and longitudinal energy distributions of the emitted electrons. Recently TESS has been upgraded to increase the instrument sensitivity for operation with low QE materials under UV illumination. Our R&D facilities also include in-vacuum quantum efficiency measurement, XPS, STM, plus ex-vacuum optical and STM microscopy for surface metrology. Intrinsic photocathode emittance is affected by many factors including illumination wavelength and surface roughness. We present energy distribution measurements for electrons emitted from copper, niobium and zirconium photocathode samples with measured levels of surface roughness under illumination by wavelengths between 256 and 291 nm. We also present an update on progress to establish a multi-alkali photocathode preparation facility to support the CLARA** linear accelerator. * Proc. FEL’13, TUPPS033, 290-293 ** CLARA Conceptual Design Report J. Inst. 9 T05001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC17
About •	paper received ※ 04 October 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
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WEPNEC21	Decoupling Cathode and Lattice Emittance Contributions from a 100 pC, 100 MeV Electron Injector System	emittance, electron, cavity, FEL	112
	N.P. Norvell SLAC, Menlo Park, California, USA M.B. Andorf, I.V. Bazarov, C.M. Gulliford, J.M. Maxson Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We present simulation results to decouple the emittance contributions that are intrinsic from the injector lattice versus emittance contributions due to the quality of the cathode out of a 100 MeV electron injector system. Using ASTRA driven by the NSGA-II genetic algorithm, we optimized the LCLS-II injector system with a zero emittance cathode. We then imposed FEL specific energy constraints and show how the Pareto Front solution shifts. Lastly, we reoptimized at various cathode emittances to map out the dependence of cathode emittance versus final emittance out of the injector system. We then determined the cathode quality needed to hit a 0.1 mm mrad 95% rms transverse emittance specification out of the current LCLS-II injector system.
	Poster WEPNEC21 [3.227 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC21
About •	paper received ※ 01 October 2019 paper accepted ※ 07 November 2019 issue date ※ 24 June 2020
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WEPNEC25	Research on Alkali Antimonide Photocathode Fabrication Recipe at PKU	emittance, laser, vacuum, electron	120
	D.M. Ouyang, L.W. Feng, S. Huang, K.X. Liu, S.W. Quan, H.M. Xie, X.K. Zhang, S. Zhao PKU, Beijing, People’s Republic of China
	Low emittance, high QE and long lifetime photocathode is widely studied for X-ray Free Electron Laser (XFEL)and Energy Recovery Linacs (ERL) applications. A deposition system for alkali antimonide photocathode (K2CsSb, Cs3Sb etc.) is being commissioned at Peking University. In this paper, we present our experimental results on alkali antimonide photocathode with this deposition system. We successfully fabricated Cs3Sb photocathode on oxygen free copper, p-type Si (100) and Mo substrates with QE of 1.4%, 2.6% and 2.6% respectively.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC25
About •	paper received ※ 27 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
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THCOYBS01	Metal and Semiconductor Photocathodes in HZDR SRF Gun	gun, SRF, laser, cavity	142
	R. Xiang, A. Arnold, P. Murcek, J. Schaber, J. Teichert HZDR, Dresden, Germany J. Schaber TU Dresden, Dresden, Germany
	Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1. Quality of photocathode in a photoinjector is one of the critical issues for the stability and reliability of the whole accelerator facility. In April 2013, the IR FEL lasing was demonstrated for the first time with the electron beam from the SRF gun with Cs2Te at HZDR. Cs2Te photocathode worked in SRF gun-I for more than one year without degradation. Currently, Mg photocathodes with QE up to 0.5% are applied in SRF Gun-II, generating e^- beam with bunch charge up to 300 pC in CW mode with sub-ps bunch length for the high power THz radiation. It is an excellent demonstration that SRF guns can work reliably in a high power user facility.
	Slides THCOYBS01 [3.868 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOYBS01
About •	paper received ※ 18 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
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THCOYBS02	High Charge High Current Beam From BNL 113 MHz SRF Gun	gun, cavity, laser, electron	145
	I. Pinayev, I. Ben-Zvi, J.C. Brutus, M. Gaowei, T. Hayes, Y.C. Jing, V. Litvinenko, J. Ma, K. Mihara, G. Narayan, I. Petrushina, F. Severino, K. Shih, J. Skaritka, E. Wang, G. Wang, Y.H. Wu BNL, Upton, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA I. Petrushina, Y.H. Wu SUNY SB, Stony Brook, New York, USA K. Shih SBU, Stony Brook, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The 113 MHz superconducting gun is used an electron source for the coherent electron cooling experiment. The unique feature of the gun is that a photocathode is held at room temperature. It allowed to preserve the quantum efficiency of Cs2KSb cathode which is adversely affected by cryogenic temperatures. Relatively low frequency permitted fully realize the accelerating field gradient what in turn helps to achieve 10 nC charge and 0.3 microns normalized emittance. We present the achieved performance and operational experience as well.
	Slides THCOYBS02 [4.350 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOYBS02
About •	paper received ※ 03 September 2019 paper accepted ※ 08 July 2020 issue date ※ 24 June 2020
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FRCOXBS05	Adjusting BERLinPro Optics to Commissioning Needs	linac, optics, bunching, gun	165
	B.C. Kuske, M. McAteer HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association BERLinPro is an Energy Recovery Linac (ERL) project currently being set up at HZB, Berlin. During the turn of the project, many adaptations of the optics to changing hardware realities were necessary. To name only one, commissioning of the recirculator will now be realized with the superconducting linac module fabricated for the Mainz ERL project MESA, as the BERLinPro linac is delayed. The Mainz linac will supply roughly 60% of the energy planned for the BERLinPro linac module and will be limited by higher order modes in the cavities to few mA of current. While the adapted optics shows similar parameters as the original 50MeV optics, studies of longitudinal space charge and coherent synchrotron radiation show that the energy leads to large emittance blow up due toμbunching. Furthermore, preparations for commissioning with gun fields much lower than the original 30MV/m in the 1.4 cell SRF gun are introduced and according optics are presented.
	Slides FRCOXBS05 [9.766 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-FRCOXBS05
About •	paper received ※ 19 September 2019 paper accepted ※ 04 November 2019 issue date ※ 24 June 2020
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Paper

Title

Other Keywords

Page

MOCOXBS04

The Berlin Energy Recovery Linac Project BERLinPro - Status, Plans and Future Opportunities

cavity, linac, gun, operation

8

M. Abo-Bakr, N. Al-Saokal, W. Anders, Y. Bergmann, K. Bürkmann-Gehrlein, A. Bundels, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, S. Heling, J.G. Hwang, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, J. Kühn, B.C. Kuske, J. Kuszynski, A.N. Matveenko, M. McAteer, A. Meseck, S. Mistry, R. Müller, A. Neumann, N. Ohm, K. Ott, F. Pflocksch, L. Pichl, J. Rahn, O. Schüler, M. Schuster, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany
H. Huck
DESY Zeuthen, Zeuthen, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association
The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a SRF based demonstration facility for the science and technology of ERLs for future high power, high brilliance electron beam applications. BERLinPro was designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. Given the recent prioritization of the BESSY II upgrade to the BESSY VSR variable pulse length storage ring, HZB is forced to reduce the project goals of BERLinPro. As a result, the project had to be rescoped with the goal to maximize its scientific impact within the present boundary conditions. We report on the last year’s progress of the building, the warm and cold infrastructure and on the time line, goals nd opportunities for the remaining project run time.

Slides MOCOXBS04 [13.980 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-MOCOXBS04

About •

paper received ※ 16 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020

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WECOXBS02

High Current Performance of Alkali Antimonide Photocathode in LEReC DC Gun

operation, gun, electron, synchrotron

61

M. Gaowei, J. Cen, A.V. Fedotov, D. Kayran, D. Lehn, C.J. Liaw, T. Rao, J.E. Tuozzolo, J. Walsh, E. Wang
BNL, Upton, New York, USA

The bi-alkali antimonide photocathode are chosen as the electron source material for the Low Energy RHIC electron Cooling (LEReC) project at RHIC, BNL based on its requirement for high bunch charge and long-time beam operation. This report presents the design and operation of the cathode deposition and transportation systems for the LEReC photocathodes, the cathode performance under the high current operation in the LEReC DC gun, as well as the characterization of the damaged cathodes from the long-time operation.

Slides WECOXBS02 [2.804 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WECOXBS02

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paper received ※ 17 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020

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WECOXBS03

Bench Test Results of CW 100 mA Electron RF Gun for Novosibirsk ERL based FEL

cavity, gun, radiation, electron

65

V. Volkov, V.S. Arbuzov, E. Kenzhebulatov, E.I. Kolobanov, A.A. Kondakov, E.V. Kozyrev, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, A.A. Murasev, V.K. Ovchar, V.M. Petrov, A.M. Pilan, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, S.S. Serednyakov, O.A. Shevchenko, S.V. Tararyshkin, A.G. Tribendis, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia
E.V. Kozyrev, S.S. Serednyakov, N.A. Vinokurov
NSU, Novosibirsk, Russia
A.G. Tribendis
NSTU, Novosibirsk, Russia
N.A. Vinokurov
KAERI, Daejon, Republic of Korea
N.A. Vinokurov
UST, Daejeon City, Republic of Korea
N.A. Vinokurov
University of Science and Technology of Korea (UST), Daejeon, Republic of Korea

Continuous wave (CW) 100 mA electron rf gun for injecting the high-quality 300-400 keV electron beam in Novosibirsk Energy Recovery Linac (ERL) and driving Free Electron Laser (FEL) was developed, built, and commissioned at BINP SB RAS. The RF gun consists of normal conducting 90 MHz rf cavity with a gridded thermionic cathode unit. Bench tests of rf gun is confirmed good results in strict accordance with our numerical calculations and showed reliable work, unpretentious for vacuum conditions and stable in long-term operation. The design features of different components of the rf gun are presented. Preparation and commissioning experience is discussed. The latest beam results are reported.

Slides WECOXBS03 [3.201 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WECOXBS03

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paper received ※ 14 September 2019 paper accepted ※ 11 November 2019 issue date ※ 24 June 2020

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WEPNEC13

Preliminary Investigations and Pre-Research Scheme of High Average Current Electron Injectors at IMP

electron, gun, high-voltage, SRF

90

Q.T. Zhao, J.C. Yang, Z.M. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

High average current electron injectors are desired by high average beam power SRF linacs. With respect to the different linac application, different beam qualities are required. Two kinds of electron gun are planned for future projects at IMP, one is thermionic electron gun dedicated for high average current, and another one is photocathode gun which is for high average current and high beam quality or even with high polarization. Current status and development of the high average current electron source are investigated and summarized. The thermionic gun studies are planned and the feasible types of gun for the future Electron ion collider of China (EicC) project are also proposed. The pre-research scheme of these two kinds of electron guns are schemed, which will be the start of high average current and high-quality electron source development at Institute of modern physics (IMP), Chinese academy of sciences (CAS).

Poster WEPNEC13 [0.827 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC13

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paper received ※ 22 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

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WEPNEC17

Developments in Photocathode R&D at STFC Daresbury Laboratory: New Transverse Energy Spread Measurements and the Development of a Multi-Alkali Photocathode Preparation Facility

vacuum, electron, emittance, laser

103

L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
L.B. Jones, D.P. Juarez-Lopez, B.L. Militsyn, T.C.Q. Noakes, L.A.J. Soomary, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D.P. Juarez-Lopez, L.A.J. Soomary, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Photocathode R&D activity within ASTeC is focussed on further development of the tools required for the preparation and characterisation of high performance photocathodes for X-FELs. Our Transverse Energy Spread Spectrometer (TESS)* experimental facility can be used with III-V semiconductor, multi-alkali and metal photocathodes to measure transverse and longitudinal energy distributions of the emitted electrons. Recently TESS has been upgraded to increase the instrument sensitivity for operation with low QE materials under UV illumination. Our R&D facilities also include in-vacuum quantum efficiency measurement, XPS, STM, plus ex-vacuum optical and STM microscopy for surface metrology. Intrinsic photocathode emittance is affected by many factors including illumination wavelength and surface roughness. We present energy distribution measurements for electrons emitted from copper, niobium and zirconium photocathode samples with measured levels of surface roughness under illumination by wavelengths between 256 and 291 nm. We also present an update on progress to establish a multi-alkali photocathode preparation facility to support the CLARA** linear accelerator.
* Proc. FEL’13, TUPPS033, 290-293
** CLARA Conceptual Design Report J. Inst. 9 T05001

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC17

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paper received ※ 04 October 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

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WEPNEC21

Decoupling Cathode and Lattice Emittance Contributions from a 100 pC, 100 MeV Electron Injector System

emittance, electron, cavity, FEL

112

N.P. Norvell
SLAC, Menlo Park, California, USA
M.B. Andorf, I.V. Bazarov, C.M. Gulliford, J.M. Maxson
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We present simulation results to decouple the emittance contributions that are intrinsic from the injector lattice versus emittance contributions due to the quality of the cathode out of a 100 MeV electron injector system. Using ASTRA driven by the NSGA-II genetic algorithm, we optimized the LCLS-II injector system with a zero emittance cathode. We then imposed FEL specific energy constraints and show how the Pareto Front solution shifts. Lastly, we reoptimized at various cathode emittances to map out the dependence of cathode emittance versus final emittance out of the injector system. We then determined the cathode quality needed to hit a 0.1 mm mrad 95% rms transverse emittance specification out of the current LCLS-II injector system.

Poster WEPNEC21 [3.227 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC21

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paper received ※ 01 October 2019 paper accepted ※ 07 November 2019 issue date ※ 24 June 2020

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WEPNEC25

Research on Alkali Antimonide Photocathode Fabrication Recipe at PKU

emittance, laser, vacuum, electron

120

D.M. Ouyang, L.W. Feng, S. Huang, K.X. Liu, S.W. Quan, H.M. Xie, X.K. Zhang, S. Zhao
PKU, Beijing, People’s Republic of China

Low emittance, high QE and long lifetime photocathode is widely studied for X-ray Free Electron Laser (XFEL)and Energy Recovery Linacs (ERL) applications. A deposition system for alkali antimonide photocathode (K2CsSb, Cs3Sb etc.) is being commissioned at Peking University. In this paper, we present our experimental results on alkali antimonide photocathode with this deposition system. We successfully fabricated Cs3Sb photocathode on oxygen free copper, p-type Si (100) and Mo substrates with QE of 1.4%, 2.6% and 2.6% respectively.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC25

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paper received ※ 27 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

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THCOYBS01

Metal and Semiconductor Photocathodes in HZDR SRF Gun

gun, SRF, laser, cavity

142

R. Xiang, A. Arnold, P. Murcek, J. Schaber, J. Teichert
HZDR, Dresden, Germany
J. Schaber
TU Dresden, Dresden, Germany

Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.
Quality of photocathode in a photoinjector is one of the critical issues for the stability and reliability of the whole accelerator facility. In April 2013, the IR FEL lasing was demonstrated for the first time with the electron beam from the SRF gun with Cs2Te at HZDR. Cs2Te photocathode worked in SRF gun-I for more than one year without degradation. Currently, Mg photocathodes with QE up to 0.5% are applied in SRF Gun-II, generating e^- beam with bunch charge up to 300 pC in CW mode with sub-ps bunch length for the high power THz radiation. It is an excellent demonstration that SRF guns can work reliably in a high power user facility.

Slides THCOYBS01 [3.868 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOYBS01

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paper received ※ 18 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

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THCOYBS02

High Charge High Current Beam From BNL 113 MHz SRF Gun

gun, cavity, laser, electron

145

I. Pinayev, I. Ben-Zvi, J.C. Brutus, M. Gaowei, T. Hayes, Y.C. Jing, V. Litvinenko, J. Ma, K. Mihara, G. Narayan, I. Petrushina, F. Severino, K. Shih, J. Skaritka, E. Wang, G. Wang, Y.H. Wu
BNL, Upton, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
I. Petrushina, Y.H. Wu
SUNY SB, Stony Brook, New York, USA
K. Shih
SBU, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 113 MHz superconducting gun is used an electron source for the coherent electron cooling experiment. The unique feature of the gun is that a photocathode is held at room temperature. It allowed to preserve the quantum efficiency of Cs2KSb cathode which is adversely affected by cryogenic temperatures. Relatively low frequency permitted fully realize the accelerating field gradient what in turn helps to achieve 10 nC charge and 0.3 microns normalized emittance. We present the achieved performance and operational experience as well.

Slides THCOYBS02 [4.350 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOYBS02

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paper received ※ 03 September 2019 paper accepted ※ 08 July 2020 issue date ※ 24 June 2020

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FRCOXBS05

Adjusting BERLinPro Optics to Commissioning Needs

linac, optics, bunching, gun

165

B.C. Kuske, M. McAteer
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association
BERLinPro is an Energy Recovery Linac (ERL) project currently being set up at HZB, Berlin. During the turn of the project, many adaptations of the optics to changing hardware realities were necessary. To name only one, commissioning of the recirculator will now be realized with the superconducting linac module fabricated for the Mainz ERL project MESA, as the BERLinPro linac is delayed. The Mainz linac will supply roughly 60% of the energy planned for the BERLinPro linac module and will be limited by higher order modes in the cavities to few mA of current. While the adapted optics shows similar parameters as the original 50MeV optics, studies of longitudinal space charge and coherent synchrotron radiation show that the energy leads to large emittance blow up due toμbunching. Furthermore, preparations for commissioning with gun fields much lower than the original 30MV/m in the 1.4 cell SRF gun are introduced and according optics are presented.

Slides FRCOXBS05 [9.766 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-FRCOXBS05

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paper received ※ 19 September 2019 paper accepted ※ 04 November 2019 issue date ※ 24 June 2020

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